From: "Michel Dänzer" <michel@daenzer•net>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: paulus@samba•org, linuxppc-dev@lists•ozlabs.org,
linux-kernel@vger•kernel.org, Ian Munsie <imunsie@au1•ibm.com>
Subject: Re: Introduce support for little endian PowerPC
Date: Mon, 04 Oct 2010 12:30:42 +0200 [thread overview]
Message-ID: <1286188242.15020.349.camel@thor.local> (raw)
In-Reply-To: <1285966204.2463.137.camel@pasglop>
On Sam, 2010-10-02 at 06:50 +1000, Benjamin Herrenschmidt wrote:=20
> On Fri, 2010-10-01 at 18:20 +0200, Michel D=C3=A4nzer wrote:
> > On Fre, 2010-10-01 at 22:14 +1000, Benjamin Herrenschmidt wrote:=20
> > >=20
> > > Now, the main reasons in practice are anything touching graphics.
> > >=20
> > > There's quite a few IP cores out there for SoCs that don't have HW
> > > swappers, and -tons- of more or less ugly code that can't deal with n=
on
> > > native pixel ordering (hell, even Xorg isn't good at it, we really on=
ly
> > > support cards that have HW swappers today).
> >=20
> > That's not true. Even the radeon driver doesn't really need the HW
> > swappers anymore with KMS.
>=20
> And last I looked X still pukes if you give it a pixmap in non native
> byte order but that might have been fixed.
I'm not sure what exactly you mean by that, but I'm not aware of any
such issues offhand.
> > > There's an even bigger pile of application code that deals with graph=
ics
> > > without any regard for endianness and is essentially unfixable.
> >=20
> > Out of curiosity, what kind of APIs are those apps using? X11 and OpenG=
L
> > have well-defined semantics wrt endianness, allowing the drivers to
> > handle any necessary byte swapping internally, and IME the vast majorit=
y
> > of apps handle this correctly.
>=20
> So why is it so hard to get any video card working on ppc ? :-)
I didn't say anything about that, just that IME it should be mostly
possible to deal with endianness within the driver stack.
Note that I'm not arguing against these changes, just pointing out some
apparent inaccuracies in the reasoning for them.
--=20
Earthling Michel D=C3=A4nzer | http://www.vmware.c=
om
Libre software enthusiast | Debian, X and DRI developer
next prev parent reply other threads:[~2010-10-04 10:30 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-01 7:05 Introduce support for little endian PowerPC Ian Munsie
2010-10-01 7:05 ` [PATCH 01/18] powerpc: Add ability to build little endian kernels Ian Munsie
2010-10-01 9:18 ` Kumar Gala
2010-10-01 11:28 ` Josh Boyer
2010-10-01 12:09 ` Benjamin Herrenschmidt
2010-10-01 11:40 ` Josh Boyer
2010-10-01 12:22 ` Benjamin Herrenschmidt
2010-10-01 7:05 ` [PATCH 02/18] powerpc: Add CROSSBE_COMPILE to build big endian boot wrapper Ian Munsie
2010-10-01 7:13 ` Geert Uytterhoeven
2010-10-01 7:19 ` Ian Munsie
2010-10-01 7:05 ` [PATCH 03/18] powerpc: Support parsing a little endian kernel from zImage wrapper Ian Munsie
2010-10-01 7:05 ` [PATCH 04/18] powerpc: Allow taishan platform to boot a little endian kernel Ian Munsie
2010-10-01 7:05 ` [PATCH 05/18] powerpc: Wire up 44x little endian boot for remaining 44x targets Ian Munsie
2010-10-01 11:27 ` Josh Boyer
2010-10-06 1:28 ` Ian Munsie
2010-10-06 1:55 ` Josh Boyer
2010-10-06 2:10 ` Sean MacLennan
2010-10-01 7:05 ` [PATCH 06/18] powerpc 44x: Set E bit in TLBs and PTEs when CPU is in little endian mode Ian Munsie
2010-10-01 7:06 ` [PATCH 07/18] powerpc: Use generic bitops for little endian bitmap operations Ian Munsie
2010-10-01 7:06 ` [PATCH 08/18] powerpc: Include the appropriate endianness header Ian Munsie
2010-10-01 7:06 ` [PATCH 09/18] powerpc: Support device tree regardless of CPU endianness Ian Munsie
2010-10-03 3:15 ` Grant Likely
2010-10-03 6:22 ` Benjamin Herrenschmidt
2010-10-01 7:06 ` [PATCH 10/18] powerpc: Support endian agnostic MMIO Ian Munsie
2010-10-01 7:06 ` [PATCH 11/18] powerpc: Make assembly endian agnostic when accessing 64bit values Ian Munsie
2010-10-01 7:06 ` [PATCH 12/18] powerpc 44x: Handle TLB miss regardless of endianness Ian Munsie
2010-10-01 7:06 ` [PATCH 13/18] powerpc 44x: Make DCR endianness agnostic Ian Munsie
2010-10-01 7:06 ` [PATCH 14/18] powerpc, of_serial: Endianness issues setting up the serial ports Ian Munsie
2010-10-07 23:23 ` Grant Likely
2010-10-01 7:06 ` [PATCH 15/18] mtd: Fix endianness issues from device tree Ian Munsie
2010-10-01 19:29 ` Artem Bityutskiy
2010-10-01 7:06 ` [PATCH 16/18] powerpc: Fix endianness issues in alignment handler Ian Munsie
2010-10-01 7:06 ` [PATCH 17/18] net: Fix endianess issues in IBM newemac driver Ian Munsie
2010-10-01 7:06 ` [PATCH 18/18] powerpc: Fix jiffies variable on little endian Ian Munsie
2010-10-01 9:02 ` Introduce support for little endian PowerPC Kumar Gala
2010-10-01 11:30 ` Josh Boyer
2010-10-01 11:55 ` Gary Thomas
2010-10-01 12:15 ` Benjamin Herrenschmidt
2010-10-01 12:37 ` Gary Thomas
2010-10-01 12:14 ` Benjamin Herrenschmidt
2010-10-01 16:20 ` Michel Dänzer
2010-10-01 20:50 ` Benjamin Herrenschmidt
2010-10-04 10:30 ` Michel Dänzer [this message]
2010-10-04 22:50 ` Benjamin Herrenschmidt
2010-10-01 17:59 ` Kumar Gala
2010-10-01 20:51 ` Benjamin Herrenschmidt
2010-10-01 22:03 ` Olof Johansson
2010-10-01 22:28 ` Benjamin Herrenschmidt
2010-10-07 16:25 ` Hollis Blanchard
2010-10-01 11:36 ` Josh Boyer
2010-10-01 12:21 ` Benjamin Herrenschmidt
2010-10-06 1:04 ` Ian Munsie
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